This invention relates to ladders. In particular, it relates to a ladder assembly formed from a plurality of ladder segments. The ladder segments are easy to carry, convenient to store, and simple to connect to construct the ladder assembly desired. These features appeal to outdoorsmen who desire to transport an elevating structure into the field for hunting and observation purposes. More specifically, the disclosed ladder segments feature a third rail that imparts extraordinary strength and stability to each segment and, ultimately, to the ladder assembly. Ladder segments having enhanced strength and stability can be constructed of lighter weight materials, and lighter weight ladder segments inherently have greater portability and utility in the field.